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Posted: Tue Oct 20, 2009 5:12 pm
by balooboat
Iwant to add an extesion to the garage which will be 4mtr x 2mtr the footings will be 300 x 200mm and the base 150mm thick, should I do the job in one go or put the footings in first and then the base

Posted: Tue Oct 20, 2009 5:39 pm
by DNgroundworks
Footings first then base, is the garage just a single skin as 300mm is to narrow a footing for a cavity wall, 200mm is a bit shy i always use the rule 10" minimum on good ground and then err on the side of caution and go a bit deeper sometimes.

150mm for the slab with visqueen should be fine

Posted: Tue Oct 20, 2009 5:41 pm
by DNgroundworks
Unless its going through building control then you building inspector will tell you how deep to go with the footings:)

Posted: Tue Oct 20, 2009 8:39 pm
by balooboat
Hi fellas, yes the garage is only single skin

Posted: Mon Oct 26, 2009 3:53 pm
by balooboat
thanks DN, I'll make the footings 10" deep, also can I use some old black plastic dpc under the base, the material is very similar to a rubble sack.

Posted: Mon Oct 26, 2009 4:20 pm
by DNgroundworks
Visqueen should be under the slab mate, available from all builders merchants.

Posted: Mon Oct 26, 2009 4:34 pm
by balooboat
thanks DN, hard times trying to save a few bob

Posted: Mon Oct 26, 2009 8:04 pm
by mickg
for the sake of a few pounds I certainly would not skimp on a roll of 100mm damp to guarantee you will not have any problems in a few years time

B and Q sell it for £6.78 a roll, stop being a tight t**t and go and buy one :p

Posted: Mon Oct 26, 2009 10:38 pm
by balooboat
I consider myself told off. I'll get some visqueen tomorrow.
Thanks everybody.
Chris